This is the place where a person usually lives. It may, or may not be the place where the person was counted on Census Night. Each person is required to state his/her address of usual residence in Question 8. The count of persons at their usual residence is known as the de jure population count.

Census counts compiled on this basis are less likely to be influenced by seasonal factors such as school holidays and snow seasons, and provide information about the usual residents of an area. More Detailed Description

There are many aspects which can affect the quality of Census data; the following information should be considered when viewing data on Place of Usual Residence (PURP).

Every person counted in the 2006 Census has been given a place of usual residence (PURP) down to the Collection District Level (CD). This differs from 2001 when 180,941 persons were unable to be coded to a CD because of insufficient address information. However all persons were given a code at the broader Statistical Local Area level, except fora small number of records (8,888) coded to state or capital city "undefined" because there was insufficient information to code below the state or capital city level.

As most people were home on Census Night, PURP is mainly obtained directly from the Collection District number assigned for that dwelling (and on the front of the census form). In 2006, 94.4% of people were counted at home on Census Night and PURP is automatically captured for 98.3% of these. The remaining 1.7% required further processing due to collection or image recognition issues. There may be a small number of cases where this number may not match the CD code for the actual address on the front of the form - for example if someone took their household form on holidays and filled it out in respect of where they were staying on Census Night. In addition a small number of forms may have an incorrect CD number. However, the risk of processing error is generally minimal.

For the 4.6% of persons who said that they lived somewhere other than the dwelling they were counted in on Census Night, the address details provided in Question 8 of the Census form needed to be coded to a CD. Of these persons, 81.1% were coded using automated processes, with the remainder being coded manually by clerical coders. Sample checks were conducted for all processes to ensure a high standard of quality. An additional 1.0% of persons stated that their usual residence was overseas and were coded as such. Provision is also made for persons who indicate on the form that they have no usual place of residence. In 2006, the number of persons coded to "No usual address" was 41,486, which was 15.2% higher than that for 2001 (36,014).

PURP is a hierarchical classification, ranging from the broadest geographical level (State/Territory) at the top of the hierarchy to the finest level (CD) at the lowest. Where there was insufficient information to address code to any level of the PURP hierarchy then that value was imputed. The imputation rate where all levels of the hierarchy where imputed is 5.4% and for the lowest level, the CD it was 5.8%. This indicates a very small number of people that did provide some higher level address information such as State or Capital City, or information that enabled PURP to be coded to a broader level of the hierarchy.

Most of the imputation is attributable to the 4.1% of persons (including those imputed as overseas visitors) in dwellings which were occupied on Census Night but did not return a completed form. Persons are imputed into these dwellings together with some demographic characteristics such as PURP. Note that 89.5% of these were imputed as being at home on Census Night.

The ABS aims to produce high quality data from the Census. To achieve this, extensive effort is put into Census form design, collection procedures, and processing procedures.

There are four principal sources of error in Census data: respondent error, processing error, partial response and undercount. Quality management of the Census program aims to reduce error as much as possible, and to provide a measure of the remaining error to data users, to allow them to use the data in an informed way.

When completing their Census form, some people do not answer all the questions which apply to them. In these instances, a 'not stated' code is allocated during processing, with the exception of non-response to age, sex, marital status and place of usual residence. These variables are needed for population estimates, so they are imputed using other information on the Census form, as well as information from the previous Census.

The processing of information from Census forms is now mostly automated, using scanning, Intelligent Character Recognition and other automatic processes. Quality assurance procedures are used during Census processing to ensure processing errors are kept at an acceptable level. Sample checking is undertaken during coding operations, and corrections are made where necessary.

The Census form may be completed by one household member on behalf of others. Incorrect answers can be introduced to the Census form if the respondent does not understand the question or does not know the correct information about other household members. Many of these errors remain in the final data.

More detailed information on data quality is available in the 2006 Census Dictionary (cat. no. 2901.0), in the section titled Managing Census Quality.